OBIRCH (Optical Beam Induced Resistance Change) method has been known as a prior art non-destructive testing method for electronic components (objects to be tested) such as semiconductor chips. In the OBIRCH method, wirings are heated when laser light is scanned over a semiconductor chip and changes in wiring resistance which is caused by heating with irradiation of laser light, are imaged. In accordance with this method, the wirings through which currents flow can be visualized. Since the level of temperature elevation is different between a position where there is a defect such as void and a position where there is no defect, the defect can be identified on the image (refer to non-Paten Reference 1). FIG. 13 is a basic principle view showing a related art non-destructive testing apparatus using the OBIRCH method. Wiring 4 is formed on a semiconductor chip which is an object 1 to be tested. The wiring 5 is connected at one end thereof with a voltage supply source 5 and is connected at the other end thereof with a current change detecting unit 6, so that a change in resistance of the wiring 4 is detected. In the OBIRCH method, an optical spot 3 which is formed by condensing a laser beam 2 to be scanned on and along the object 1 to be tested, so that a change in resistance of the wiring when it is heated is imaged. In accordance with the OBIRCH method, the wiring through which current flows can be visualized and the temperature elevation is different between a position where there is a defect such as void in the wiring and a position where there is no defect. Therefore, the defect can be identified on the image. FIG. 14 shows a two-dimensional image which is obtained by the foregoing method. An image of wiring 4 and an image of a defect 8 are visualized at an observation area 7.
RIL (Resistive Interconnection Localization) method or SDL (Soft Defect Localization) method which is a denomination more common than the RIL method has been known as prior art non-destructive testing method for electronic components such as semiconductor chips. If this method is used, a dynamic defect or fault analysis of defective component which is marginal with respect to temperature, power source voltage and operation frequency can be conducted. Semiconductor chips are sequentially heated by slowly scanning laser light on the chips to conduct testing of functions with a LSI tester for pass/fail testing. Dynamic determination of abnormal position is made possible by displaying a result of pass/fail testing in the LSI tester in monochrome on a pixel-by-pixel basis relative to the position where irradiation with laser light is conducted (refer to non-patent reference 1).
OBIC (Optical Beam Induced Current) method has also been known as prior art non-destructive method for electronic component (object to be tested) such as LSI chip. The OBIC method exploits a phenomenon in which pairs of electrons and holes which are excited by light are separated and are observed as currents. A source of an internal electrostatic field for separating pairs of electrons and holes may include a p-n junction and an impurity concentration gradient. An electrostatic field which is induced by an external application of a voltage may be used. Since a way of applications of internal and external electrostatic fields is different in the presence of short circuit and broken wire, fault position can be identified (refer to non-patent reference 1).
Furthermore, SCOBIC (Single Contact OBIC) method and scanned laser SQUID (Superconducting Quantum Interference Devices) microscope (L-SQ) method have been known as a failure analyzing technique which belongs to the OBIC system. In the OBIC method, an observation between two terminals is conducted, which restricts an OBIC generation path. If connection to only one terminal and observation is conducted, restriction of the OBIC generation path is mitigated, so that more positions can be observed. This method is referred to as “SCOBIC”.
A method in which observation of current is not conducted from an external terminal, but a magnetic field which is generated by an OBIC current is observed by means of SQUID which is a magnetic field detector having a ultra-high sensitivity has been proposed. This method is referred to as “L-SQ” method. This method enables completely non-contact analysis which does not require even electrical connection. A sample which can be observed may include various forms such as wafers in the course of previous to step, in the course of wiring step, after completion of wafer step, after packaging and after mounting (refer to Non-Patent Document 1).
LTEM (Laser Terahertz Emission Microscope) method has been known as a prior art non-destructive testing method for electronic components (objects to be tested) such as semiconductor chips. In the LTEM method, Terahertz electromagnetic waves are detected which are radiated by transient optical current generated when a portion in which an electrostatic field exists such as p-n junction is irradiated with femto second laser. Data which suggest the possibility of observation of the operation of high speed device by the LTEM method is reported. It also reports the possibility of non-bias LTEM method which is a non-contact analysis which does not require even electrical connection as is similar to L-SQ method (refer to non-patent reference 1).
[Non-Patent Document 1]
Kiyoshi NIKAWA, “Optical Tools and Techniques for Failure Analysis of LSIs”, Journal of JAPAN society of Reliability “Reliability” (REAJ), Vol. 26, No. 1, pp 28 to 36 (2004).